Closed loop system for the manufacture and handling of concrete pipe

ABSTRACT

An improved method for moving a large, heavy, fragile, freshly-made concrete pipe section, with top and bottom pallets but without jacket protection, out of a casting machine, and directly into a kiln, for curing; moving the cured pipe section from the kiln to an unloading station, automatically removing the top pallet, removing the pipe section from the bottom pallet, cleaning the top pallet and then placing the top pallet on a reinforcing cage that has been set on the bottom pallet, ready for the next cycle. The cycle is continuously intermittant.

This application is a continuation of application Ser. No. 853,205 filedApr. 17, 1986, now abandoned.

The present invention relates to a closed loop system for themanufacture and handling of reinforced concrete pipe. More particularly,the present invention relates to an improved method and apparatus formoving a large, heavy, fragile, freshly-made concrete pipe section, withtop and bottom pallets but without jacket protection, out of a castingmachine and directly into a kiln for curing; moving the cured pipesection from the kiln to an unloading station; automatically removingthe top pallet from the pipe section; removing the pipe section from thebottom pallet; cleaning the top pallet and then placing the top palleton a reinforcing cage that has been set on the bottom pallet, ready forthe next cycle.

BACKGROUND OF THE INVENTION

In the manufacture of reinforced concrete pipes in a vertical position,two different concepts are used that are generally referred to as (1),wet cast, and (2), dry cast.

In the wet cast operation, high slump concrete is used and is pouredinto a liquid tight form. The concrete mix generally stays in the formfor 24 hours, so the concrete can harden. Then the forms and pallets areremoved. Production is limited to the number of (expensive) forms andpallets that are available. This concept is well suited to producingvery large pipe.

In the dry cast operation, no slump concrete is used in the formation ofthe concrete pipe. The jacket and core and sometimes the top pallet areremoved immediately after the pipe has been formed.

In placing no slump concrete into vertical forms, generally, threedifferent methods are used to densify the mix sufficiently, so that thepipe will not collapse when the forms are removed.

In the first dry cast method, the mix is placed into the forms andpacked or densified by tamping in a tamping machine.

In the second dry cast method, the mix is placed in the form and ispacked by rollers in a packerhead machine.

In the third dry cast method, the mix is placed in the forms andvibrated, causing the mix to turn into a semifluid mix and to settle anddensify. Reference is made to U.S. Pat. Nos. 3,584,356 and 3,696,182.

When the vibration ceases, the fluid mix reverts back to a firm, dense,and relatively stable mix, so that forms can be removed immediately,without causing the newly made pipe to collapse.

The present invention relates in part, to the third method. In using thethird method, the pipe is formed in the machine, and then the jacket andcore, that are a part of the machine, are stripped from the pipe,leaving the pipe in the machine supported only by its bottom pallet.

Customarily, two procedures of moving the pipe from the machine to thecuring area are utilized.

In the first procedure, the newly made pipe on its bottom pallet (withor without a top pallet) is slowly and carefully raised off of themachine's saddle by a fork truck, which then has to reverse to back outof the machine, then stop to shift gears, then turn to proceed to thecuring area, then lower the pipe with its pallet to the floor, thenreverse to clear the pipe and pallet, then stop and turn and proceed tothe casting machine for another pipe.

In the second procedure the newly made pipe is moved out of the machineby an off-bearing apparatus, which inserts its forks under the outsideedges of the bottom pallet, then raises the pipe with its bottom pallet,off of the saddle. Then the forks, which are attached to an overheadcarriage which rides on an overhead track (rails), move the pipe andbottom pallet out from under the machine and lowers and deposits thepipe and lower pallet onto a moving floor that generally runs at rightangle to the machine.

This apparatus, when automated, eliminates the need of a fork truck andoperator.

In either procedure, the forks raise the pallet, with the forks beingpositioned on the outer circumference of the pallet. The weight oflarger pipe will cause the section in the middle of the pallet to sag,progressively more, as pallet size increases. This sagging causes cracksand the pulling of the concrete away from the reinforcing wires,sometimes causing pieces of the green pipe to fall off, or the pipe tocollapse.

These two systems of removing the forms from the pipe in the machine andthen removing the pipe from the machine on only its bottom pallet, arewell suited to pipes from 12" to 36" in dia., due to the fact that inthese smaller sizes, the bottom pallets are relatively rigid.

In pipe of larger sizes, i.e. 48" to 96" plus, the difficulty of safelyremoving these sizes of pipe from the machine, becomes progressivelygreater as sizes increase.

Because of this sagging problem with larger pipe, another procedure iswidely used, in which the forms are filled with no slump concrete at acentral filling station, and vibrated. Then a top pallet is manuallyplaced on top of the mix to form a tongue (or groove).

The pipe in this form is then transported by overhead crane orfork-truck to the curing area. The forms are manually removed and thepipe left standing on its bottom pallet.

The top pallets weighing as much as 400 lbs. are removed from cured pipein the curing area by hooks attached to an overhead crane or fork-truck,then moved to an area adjacent to the filling station, then lowered andcleaned, then after the form is filled, the top pallet is raised andplaced on top of the mix to form the tongue, then tranported again tothe curing area. All of this is accomplished in close proximity to 3 or4 men, which creates a hazardous situation.

The forms which have been removed from the pipe are manually reassembledaround another bottom pallet with its reinforcing cage and the emptyform and top pallet transported back to the filling station, and thecycle repeated.

In this procedure, the green pipe has the protection of the outerjacket, which also grips the outer circumference of the bottom pallet,preventing any flexing, while being moved to the curing stage. The lossof pipe due to breaking apart is minimal.

On the other hand, these current procedures are complex, slow, costly,and hazardous in producing and handling pipe of a larger size.

It is, therefore, an object of the present invention to provide animproved means of handling large, newly-made pipe from the formingmachine through curing without harm to the pipe.

A further object of this invention is to provide a method and apparatuswhich simplifies the handling and moving of concrete pipe, both greenand cured, with top and bottom pallets.

Another object of the present invention is to provide a method andapparatus which will reduce the number of personnel required to handlethe newly-made pipe from forming machine through curing to storage.

A still further object of the present invention is to provide a methodand apparatus which will render less hazardous the handling of pipe,both green and cured on pallets.

Another object of the present invention is to provide a less costlymethod and apparatus for handling both green and cured pipe.

A still further object of the present invention is to provide anapparatus for safely handling the precision top pallets that arecompatable with the bottom pallets in making precision gasket joints.

A further object of the present invention is to provide an apparatuswhich will safely remove the top pallet from a cured pipe, clean, oiland then place it on a cage that is sitting on a pallet car, ready to bemoved to a pipe machine.

A still further object of the present invention is to provide anapparatus for clamping, lifting, removing and rotating the cured pipefrom the loop system.

A further object of this invention is to provide a system for theremoval of pallets from cured pipe for substantially immediate re-use,and stockpiling pipe that were previously manufactured during currentmanufacturing.

A still further object of the present invention is to provide a systemwhereby the pallet cars are automatically positioned in designatedrespective positions, during the manufacturing and handling cycle.

SUMMARY OF THE INVENTION

The foregoing objects have been attained by a closed loop track systemupon which cars having bottom pallets fixed thereto move. Along the loopare a pipe-section-forming unit, a kiln for curing green pipe-sections,a gantry crane for removing a top pallet from a cured pipe section,cleaning the top pallet and placing the top pallet on a reinforcing cagepositioned on a car preceding the car from which the pallet was removedand a pipe clamping and repositioning unit which clamps the pipe,removes the pipe from car and loop system and repositions the pipe foreasy removal to a storage area.

The removal, cleaning and replacement of the top pallet is accomplishedby one man with the gantry crane. With the closed loop system the palletcars are automatically positioned in their designated respectivepositions during the pipe manufacturing cycle.

The method constitutes moving a large, heavy, fragile, freshly-madeconcrete pipe section, with top and bottom pallets but without jacketprotection, out of a casting machine and directly into a kiln forcuring; moving the cured pipe section from the kiln to an unloadingstation; automatically removing the top pallet from the pipe section;removing the pipe section from the bottom pallet; cleaning the toppallet and then placing the top pallet on a reinforcing cage that hasbeen set on a bottom pallet, ready for the next cycle.

BRIEF DESCRIPTION OF THE DRAWINGS

Other details and features of the invention will stand out from thedescription given below by way of nonlimitative example and withreference to the accompanying drawings, in which:

FIG. 1 is a plan view of the closed loop system of the presentinvention;

FIG. 2 is an elevated sectional view of a pallet car of the presentinvention;

FIG. 3 is a plan view of a pallet car transfer section from line A toline B of FIG. 1;

FIG. 4 is a side elevational view partially in section of the transfersection of FIG. 3;

FIG. 5 is a plan view of a pallet car transfer section from line B toline A of FIG. 1;

FIG. 6 is a front elevational view of an apparatus, for removing a toppallet from cured pipe;

FIG. 7 is a right side view of the apparatus shown in FIG. 6;

FIG. 8 is a right side view in elevation of the driving assembly for theapparatus shown in FIG. 6;

FIG. 9 is a partial cross-sectional view along the line 9--9 of FIG. 6;

FIG. 10 is a plan view in partial section along the line 10--10 of FIG.8;

FIG. 11 is an elevational view in partial section along the line 11--11of FIG. 6;

FIG. 12 is a plan view taken along line 12--12 of FIG. 6;

FIG. 13 is an elevation view in partial section taken along line 13--13of FIG. 7.

FIG. 14 is a front elevation view in partial section of the pipeclamping and repositioning unit of the present invention;

FIG. 15 is a side elevational view of the pipe clamping andrepositioning unit of FIG. 14.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plan view of a closed loop reinforced concrete continuouspipe production system. The building in which the system is housed isdivided essentially into a section 1 for making and removing the pipeand a section 2 which is a kiln for curing the freshly produced greenpipe.

The loop system comprises a hydraulic ram 3 for intermittently movingthe pallet cars 4 along line A, a pipe forming unit 5 straddling line Afor forming pipe sections, a transfer car 6 moving between lines A and Bfor transferring a pallet car 4 from line A to line B, a hydraulic ram 7for intermittently moving pallet cars 4 along line B, a gantry crane 8for removing top pallets 9 from cured pipe 10 and placing the top palleton a reinforcing cage 11, a pipe clamping and repositioning unit 12 forremoving the cured pipe from the pallet car 4, withdrawing the pipe 10from the loop and rotating the pipe 10 for receipt by a forklift and atransfer car 13 moving between lines B and A for transferring a palletcar 4 with cage and top pallet from line B to line A.

FIG. 2 shows in detail a cross-section of a pallet car 4. Car 4 has aplatform 40 made from steel plate which is sufficiently thick to supportthe weight of the concrete pipe 10 reinforced by the wire reinforcingcage 11. The platform 40 is mounted on wheels 41 for movement along therails 42 (lines A and B). Supported on platform 40 is a bottom pallet 43shaped to form a matrix for the lower end of the concrete pipe section10. The lower pallet 43 is bolted at 44 to platform 40. On top of theconcrete pipe 10 is a top pallet 9 forming a matrix for the top end ofthe concrete pipe section 10. A flange 90 is fixed to the top of pallet9 to enable removing the top pallet 9 from the concrete pipe section 10once it is cured.

FIGS. 3 and 4 show a pallet car 4 carrying partially cured pipe, ashallow pit 60, the floor 61 of which is positioned lower than the levelof track for lines A and B, rails 62 mounted on the floor 61 of pit 60,a transfer car 6 with wheel assemblies 63 rolling on the rails 62, rails42 mounted transversely on car 6 which are level with the tracks oflines A and B so that a pallet car 4 can be rolled onto car 6 from lineA and off of car 6 onto line B.

On either end of the transfer section pit, are mounted, a reversiblemotorized, drive sprocket 64 and an idler sprocket 65 over which aroller chain 66 is passed for moving the transfer car 6 in eitherdirection. One end of the roller chain 66 is springingly attached at oneend 67 to transfer car 6. From end 67 the chain 66 passes around idlersprocket 65 under transfer car 6, around reversible motorized drivesprocket 64 and springingly attaches at 68 to the other end of transfercar 6. Since motorized drive sprocket 64 is reversible and sprocket 65is an idler, transfer car 6 can be easily pulled in either direction.

FIG. 5 shows transfer car 13 which is identical to transfer car 6. Forbrevity a detailed description is omitted.

FIGS. 6 through 13 show gantry crane 8 which removes the top pallet 9from the cured pipe 10. Referring specifically to FIGS. 6 and 7 thegantry crane 8 is composed of two horizontal base channels 80 and 81,legs 82 and 83 which are fixed at their lower ends to the ends of basechannel 80, legs 84 and 85 which are fixed at their lower ends to theends of base channel 81, top channel member 86 which is joined to legs82, 83, 84 and 85 at their upper ends to form an inverted U-shapedconfiguration in end view, two wheel assemblies 87 and 88 mounted onbase channel 80, two wheel assemblies 89 and 90 mounted on base channel81, motorized unit to raise and lower the top pallet 9, grab hook tograsp the top pallet and driving assembly to move the gantry crane 8.The gantry crane 8 rolls on rails 91 positioned outside of and parallelto the rails 42 upon which the pallet cars 4 roll. In FIGS. 8 to 10 isshown the driving assembly by which the gantry crane 8 is moved alongrails 91. On each wheel assembly 87 and 88 is mounted a sprocket 92 and93, respectively. A motor speed-reducer unit 94 is mounted on basechannel 80. Rotatable on motor speed-reducer unit 94 is a sprocket 95which drives a sprocket chain 96 mounted around sprockets 92 and 93.Chain tension adjustable sprockets 97 and 98 are mounted on base channel80. Upon activation of the motor speed-reducer unit 94 with sprockets 97and 98 forcing chain 96 into contact with sprocket 95 the gantry crane 8moves along rails 91 from the location where the top pallet 9 is removedto the location where the top pallet previously cleaned is placed on thewire reinforcing cage 11. After the gantry crane 8 positions the toppallet 9 on the wire reinforcing cage 11 it returns to the locationwhere the top pallet 9 of a cured pipe 10 is removed.

The motorized unit for raising and lowering a top pallet 9 is shown inFIGS. 11 to 13. With specific reference to FIGS. 11 and 13 there isshown top channel member 86. Mounted on channel member 86 are bearingmembers 99, 100 (not shown), 101, 102, 103 and 104 (not shown)supporting shafts 105, 106 and 107. Fixed to shaft 105 are pulleys 108and 109 only 108 of which is shown in FIG. 13. Fixed to shaft 107 arepulleys 110 and 111 only 110 of which is shown in FIG. 13. Fixed toshaft 106 are pulleys 112 and 113 each having two sheaves 114, 115 and116, 117. The sheaves 114 and 117 are aligned with pulleys 108 and 109,respectively. Sheaves 115 and 116 are aligned with pulleys 110 and 111,respectively. Also fixed on shaft 106 is a sprocket 118 which is rotatedby means of a motor speed-reducer unit 119 mounted on channel member 86and chain 120. A floating platform 121 is suspended from the channelmember 86 by means of wire ropes or roller chain 122, 123, 124 and 125having threaded end portions only two of which are shown in FIG. 13. Theplatform 121 is attached to wire ropes 122, 123, 124 and 125 by means oflocking nuts 126, 127 threaded onto the end portions thereof. Uponactivation of the motor speed-reducing unit 119 the platform 121 may beraised or lowered. The platform contains a transverse stop divider 128which divides the platform into essentially symmetrical sides. Each sidecontains a longitudinal slot 129 only one of which is shown. Slidablymounted on the slot is a grab hook 130. The grab hook 130 has a verticalend portion 131 to which is pivotally mounted an end of a piston rod 132of a hydraulic cylinder 133. The hydraulic cylinder 133 is pivotallymounted on a bracket 134, fixed to platform 121. Upon activation of thehydraulic cylinders 133 the grab hooks 130 move horizontally to takehold of or release the top pallet 9.

Since both sides of transverse stop divider 128 of platform 121 areessentially symmetrical only one has been specifically described.

In FIGS. 14 and 15 there is shown the pipe clamping and repositioningunit 12 which removes a cured vertically standing pipe 10 from a palletcar 4 and rotates the pipe through a 90° arc so that it can be picked upby a fork lift and removed to a storage area. The pipe clamping andrepositioning unit 12 is moved into position over the verticallystanding pipe by an overhead crane 220 to which the pipe clamping andrepositioning unit 12 is attached by a lifting assembly 221. The liftingassembly is comprised of chains 221a attached to brackets 221b andpassing through ring 221c. Ring 221c in turn is attached to crane 220.Brackets 221b are fixed to a box 222 which is divided into twosymmetrical sections 222a and 222b. Since both sections are the sameonly one will be described. On the bottom of each section is arectangular opening 223 (FIG. 15). A carriage 224 moves within box 222on wheels 225 and has an arm 226 extending through opening 223. Thecarriage is moved by operating a hydraulic unit 227 which has a cylinder228 attached to the end 229 of box 222 by a bracket 230 and a piston rod231 attached to a bracket 232 on carriage 224. Pivotally mounted on thearm 226 is an arcuate clamp panel 233 fixed to shaft 234. A tilting unit235 is attached to the arm 226. The tilting unit 235 is comprised of ahydraulic cylinder 236 attached to a pivotable bracket 237 fixed on arm226 and piston rod 238 attached to one end of arm 239 which is fixed toshaft 234 at its other end. The activation of hydraulic unit 227 willmove the arcuate clamp panel 233 into contact with the cured pipe 10after which the overhead crane 220 lifts the pipe 10 from the pallet car4 and removes the pipe 10 from the loop. Subsequently tilting unit 235is activated to rotate the pipe 10 from a vertical to a horizontalposition. While the pipe 10 is in the horizontal position a forkliftmoves the pipe 10 to a storage area.

DESCRIPTION OF THE OPERATION

At the beginning of a shift, and before the first cycle is started, thepallet cars 4, transfer cars 6, 13, gantry crane 8 and pipe clamping andrepositioning unit 12 are in the following positions. Line A, FIG. 1, iscompletely filled with pallet cars 4. The pallet car 4 under the pipeforming unit 5 in line A is empty i.e. without a reinforcing cage 11 andtop pallet 9 so that the pipe forming unit 5 can be cleaned betweenshifts. The remaining pallet cars 4 in line A carry verticallypositioned pipe sections 10. The transfer car 6 in the kiln does notcarry a pallet car 4 but is positioned at the end of line A to receive apallet car 4 with a pipe section 10 once the first cycle of the newshift is started. The other transfer car 13 is positioned at thebeginning of line A with a pallet car 4, a reinforcing cage 11 and toppallet 9 thereon ready for movement onto line A and into the pipe makingunit 5 once the cycle is started. Line B is completely filled withpallet cars 4 carrying pipe 10 except for the five pallet cars 4 fromwhich the pipe has been removed positioned closest to transfer car 13.The gantry crane 8 is positioned over the empty pallet car 4 in line Bfurtherest from transfer car 13. The pipe clamping and repositioningunit 12 is positioned at the side of the gantry crane 8. The pipeforming unit 5 operator to start the first cycle of the shift by his owndirection energizes ram 3 which pushes the pallet car 4 with reinforcingcage 11 and top pallet 9 on the transfer car 13 into the pipe formingunit 5. This movement in turn forces the movement of each pallet car 4 adistance equal to the length of one pallet car along line A and the lastpallet car 4 on line A onto transfer car 6. The movement of the palletcar 4 onto transfer car 6 trips a normally open switch (L.S.N.O.) whichenergizes the following semi-automatic cycles: it activates the pipeforming unit 5 and simultaneously energizes the loop cycle whichconstitutes energizing the motor drive sprockets for transfer cars 6 and13. Transfer car 6 with a pallet car thereon is moved to the beginningof line B and simultaneously transfer car 13 which is now empty is movedfrom line A to line B. When transfer car 6 with pallet car 4 and pipe 10thereon reaches the beginning of line B it trips another normally openlimit switch (L.S.N.O.), energizing ram 7, and deenergizing the motordrive sprockets for transfer cars 6 and 13. Ram 7 upon being energizedpushes pallet car 4 with pipe 10 off of transfer car 6 onto thebeginning of line B which simultaneously moves all pallet cars 4 alongline B the distance of the length of one pallet car 4. The pallet car 4with pipe 10 on line B closest to transfer car 13 is moved under gantrycrane 8. The pallet car 4 on line B carrying a cage 11 and top pallet 9which is closest to transfer car 13 is moved onto transfer car 13. Themovement of pallet car 4 carrying a cage 11 and top pallet 9 ontotransfer car 13 trips another normally open limit switch (L.S.N.O.)which energizes both the motor drive sprockets for transfer cars 6 and13 and moves transfer cars 6 and 13 from line B to line A. The trippingof the last mentioned limit switch also energizes the gantry crane 8 toremove the top pallet 9 from the pipe 10 and move the gantry crane 8 tothe position for cleaning the top pallet which is over the pallet car 4in line B which is the third closest to transfer car 13. When transfercar 13 reaches line A it trips a normally closed limit switch (L.S.N.C.)to deenergize the motorized sprockets of transfer cars 6 and 13. Thegantry crane 8 upon reaching the position for cleaning the top pallet 9trips a normally closed limit switch (L.S.N.C.) to deenergize thesemi-automatic cycle of the loop system. The deenergizing of thesemi-automatic cycle of the loop system does not affect the pipe formingunit 5. The forklift operator once the gantry crane 8 has removed thetop pallet 9 from the pallet car 4 in line B carrying the pipe 10 whichis closest to transfer car 13 moves by his own direction the pipeclamping and repositioning unit 12 over the pallet car 4 with the pipesection from which the top pallet 9 has been removed, clamps the pipe10, lifts the pipe 10 from the pallet car 4, removes the clamped pipe 10from line B, tips the pipe 10 through 90°, forklifts the pipe 10 to thestorage area, returns from the storage area and places a reinforcingcage 11 on the pallet car 4 in line B which is closest to transfer car13.

When gantry crane 8 reaches the cleaning position and stops, the pipeforming unit 5 operator cleans and oils top pallet 9, (a 3 to 5 minuteoperation), then by his own direction moves gantry crane 8 with its toppallet 9 over the cage 11 which previously has been placed on the palletcar by the forklift operator, sets the top pallet 9 on the cage 11,releases the clamp and starts gantry crane 8, back to the beginning ofits track, ready for the next cycle. The gantry crane upon reaching thebeginning of its track trips a normally closed limit switch (L.S.N.C.)to stop its movement.

Pipe forming unit 5 operator is now free to move back to pipe formingunit 5 and stop the semi-automatic cycle of pipe forming unit 5 and takeover control by his own direction, in order to finish the tongue of pipe10. The pipe forming unit 5 takes about 10-15 minutes to form a pipesection 10. When the tongue has been completed and pipe 10 partiallystripped, the header holding the top pallet 10 unlatches the top pallet9 from the header, leaving the top pallet 9 on pipe 10. The header thenrises to its top position in unit 5 where it trips a normally open limitswitch reenergizing ram 3, and starting a new cycle.

Upon bringing a shift to a close, in the next to the last cycle, theforklift operator and pipe forming unit operator do not place areinforcing cage and top pallet respectively on the last pallet car 4 inline B. However, on the last cycle, they do place a cage and top palleton the last pallet car 4 in line B to be ready for the following shift.

What is claimed is:
 1. A closed single level loop process formanufacturing and handling large, heavy reinforced concrete pipecomprising moving intermittently a reinforcing cage from a startingstation on a single level to a molding station on the same level,freshly molding a reinforced concrete pipe around said reinforcing cage,while holding the freshly molded concrete pipe only by ends of the pipe,curing said held freshly molded pipe by intermittently moving said pipethrough a curing station on the same level as said molding station,intermittently moving said cured held pipe to said starting station fromsaid curing station, releasing the pipe and repeating the cycle.